Year Number of 1990 6118.34 1991 6542.23 1992 6973.58 1993 7425.95 1994 7916.4 1995 8461.34 1996 8643.41 1997 8863.78 1998 9114.85 1999 9368.85 2000 9621.51 2001 9863.08 2002 10095.94 2003 10338.09 2004 10587.67 2005 10858.85 2006 11133.17 2007 11420.32 2008 11760.9 2009 12133.66 2010 12536.83 2011 13308.66 2012 14141.07 2013 15046.67 2014 15991.73 2015 16975.09 2016 18018.61